Triple lumen stone balloon catheter and method

ABSTRACT

A triple lumen stone balloon catheter ( 1 ) having a tapered distal end ( 9 ). A lumen ( 24 ) dedicated to transmitting contrast media is dimensioned and adapted to conform to the shape of a kidney in a main shaft of the catheter and conform to the shape of a crescent in a distal end of the catheter. The geometric shaping of the contrast media lumen ( 24 ) enables wall thickness to be maintained within acceptable ranges to sustain desirable mechanical characteristics while allowing for enhanced contrast media flow. A method for employing the balloon catheter ( 1 ) is also disclosed.

FIELD OF THE INVENTION

This invention relates generally to balloon catheters having multiplelumens. Specifically, the invention relates to triple lumen stoneballoon catheters and methods for making same.

BACKGROUND OF THE INVENTION

To provide an alternative to surgery, the medical industry devisednon-invasive procedures and products that involve utilization ofendoscopes. One such product is a stone balloon catheter. Stone ballooncatheters generally comprise a sheath or elongate tube having one ormultiple lumens with an elastic balloon situated proximal to a distalend of the sheath. One lumen is adapted to communicate with the interiorof the balloon so that a fluid or gas source attached to a proximal endof the catheter can be used to infuse either liquid or gas into theballoon to inflate it. Any other lumen provided in the catheter can beused for a variety of purposes such as providing a channel for a guidewire to direct the insertion of the catheter into the patient.

Some of the most recent developments with stone balloon technologyinvolves the use of a triple lumen catheter. Typically, such a catheterwill have one lumen dedicated to infusion and aspiration of fluids orgases into or out of the balloon to effectuate inflation and deflation.A second lumen is dedicated to receive a guide wire for placing thecatheter. A third lumen is dedicated to infuse contrast media to allowfor the fluoroscopic elucidation of the site being evaluated ormanipulated.

Triple lumen catheters are used for two primary purposes: 1) diagnosticand 2) therapeutic. A triple lumen stone balloon is designedparticularly for use as a therapeutic tool. As the name suggests, astone balloon is used to remove crystalline objects from a duct. Onesuch duct is the common bile duct of the biliary system consisting ofthe liver, gall bladder and pancreas.

One of the enduring problems associated with catheter technology is theability to quickly and effectively deliver contrast media to the desiredlocus. Due to the combination of limited lumen size and the highlyviscous nature of contrast media compositions, high levels of pressure(on the order of several atmospheres), are needed to effectuate deliveryof the contrast media.

It is thus, an object of the invention to provide a triple lumen stoneballoon that maximizes the ease and efficiency of contrast mediadelivery while maintaining infusion and aspiration rates for ballooninflation and deflation and lumen size to accommodate a guide wire. Itis a further object of the invention to maintain desirable mechanicalcharacteristics of triple lumen balloon catheters while maximizingcontrast media flow. These and other objects of the invention will beapparent from a reading of the following summary and detaileddescription of the preferred embodiment.

SUMMARY OF THE INVENTION

It has now been discovered that by balancing the relativecross-sectional areas and geometries of the lumen of a triple lumenstone balloon catheter, contrast media delivery can be maximized whilemaintaining acceptable inflation and deflation rates for expanding anddeflating a stone balloon as well as providing adequate clearance for aguide wire. The selected geometries ensure that the following mechanicalrequirements are maintained. Compatibility of the guide wire lumen toreceive in sliding engagement a .035 inch guide wire was maintained byusing an inner diameter of about .041 inches nominal in the main shaftand about .037 inches minimum at the tip length. Balloon inflation anddeflation times where maintained within acceptable ranges by reducingthe cross-sectional area of the balloon inflation lumen in the mainshaft and tip of the catheter.

To accommodate the high viscosity of contrast media that requiresrelatively high pressures to transmit the media through the main shaftof a catheter, the contrast media lumen cross-sectional area wasincreased and the shape of the contrast media lumen was adapted toconform to the shape of a kidney to maximize cross-sectional area whilemaintaining minimum wall thickness necessary to maintain the mechanicalcharacteristics of stiffness, pushability, trackability, kinkability,tensile strength and elongation. To increase the cross-sectional area ofthe contrast lumen in the tip while again maintaining minimum wallthickness, the lumen was modified to conform to the shape of a crescent.Transformation from the kidney shape to the crescent shape isaccomplished by adjusting the individual air pressures in each of thethree lumen during sheath formation via an extrusion process.

The mechanical requirements set forth above are defined as follows.Pushability is the catheter's ability to transmit axial force to allowfor transposition and placement in a particular channel or duct beingnegotiated. Trackability is the ability of a catheter to follow acoaxially placed guide wire. Stiffness is the relative stiffness valueof the catheter relative to the stiffness of other prior art catheters.Kinkability is the ability of the main shaft and the distal tip of thecatheter (approximately two inches of the shaft and tip) to sustain a180° deflection without collapse of the lumen. Tensile strength is anaxial tensile strength of greater than four pounds. Elongation is theability of the catheter to resist stretching less than five percent whena 3.5 lb. load is attached to an end of the catheter.

To achieve these goals, a catheter was formed from Pebax 7033 medicalgrade having 20% Barium Sulfate. This material was chosen in part due tothe fact that is meets the biological requirements of ISO 10993. Theblend is easy to extrude, dimensionally stable, and provides a desiredbalance of mechanical characteristics such as stiffness and flexibility.The barium sulfate component provides fluoroscopic visualizationcapability and added stiffness to the catheter.

The main shaft of the catheter has a 7 French outside diameter thattapers down to a 5 French distal tip. The distal tip has a straightcylindrical outer shape to accommodate a balloon and marker bands aswell as facilitate insertion into duct systems such as the biliary ductsystem. The 7 French diameter allows for the catheter to be used in astandard endoscope or duodenoscope having a 2.8 mm minimum workingchannel. The interluminal and exterior walls of the catheter havethickness of about 0.006 inches minimum for the main shaft and about0.004 inches minimum for the distal tip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a triple lumen balloon catheter according toone embodiment of the invention.

-   -   FIG. 2A is a fragmented elevational view of a distal end of a        triple lumen stone balloon catheter according to one embodiment        of the invention.    -   FIG 2B is a view and cross section of a distal end of a triple        lumen stone balloon catheter according to one embodiment of the        invention.

FIG. 3 is a plan view of a tube junction assembly according to oneembodiment of the invention.

FIG. 4 is a sectional view of a tube junction assembly according to oneembodiment of the invention.

FIG. 5 is cross-sectional view of a tube junction assembly according toone embodiment of the invention.

FIG. 6 is a cross-sectional view of a catheter tube according to oneembodiment of the invention.

FIG. 7 is a cross-sectional view of a catheter tube distal end withguide wire according to one embodiment of the invention.

FIG. 8 is a cross-sectional view of a catheter tube main shaft withguide wire according to one embodiment of the invention.

FIG. 9 is an elevational view of a catheter tube according to oneembodiment of the invention.

FIG. 10 is a schematic of a catheter tube manufacturing apparatus andprocess according to one embodiment of the invention.

FIG. 11 is a cross-sectional view of a distal end of a catheter tubeaccording to one embodiment of the invention.

FIG. 12 is a cross-sectional view of a main shaft end of a catheter tubeaccording to one embodiment of the invention.

FIG. 13 is a sectional view of a triple lumen balloon catheter accordingto one embodiment of the invention.

FIGS. 14A and 14B are cross-sectional views of a prior art ballooncatheter designated “A”.

FIGS. 15A and 15B are cross-sectional views of a prior art ballooncatheter designated “B”.

FIG. 16 is a cross-sectional view of a catheter with a preferred maximumcontrast medium lumen in the distal tip according to one embodiment ofthe invention.

FIG. 17 is a cross-sectional view of a catheter with a preferred minimumcontrast medium lumen in the distal tip according to another embodimentof the invention.

FIG. 18 is a cross-sectional view of a catheter with a preferred minimumcontrast medium lumen in the main shaft according to one embodiment ofthe invention

FIG. 19 is a cross-sectional view of a catheter with a preferred maximumcontrast medium lumen in the main shaft according to another embodimentof the invention.

FIG. 20 is a perspective view of a triple lumen catheter according toone embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2, 6-9 and 20, a triple lumen stone ballooncatheter, shown generally as 1, has an elongate sheath 4 with threelumens (not shown). Sheath 4 has a proximal end 6 attached to a tubejunction assembly 8 that is preferably cylindrical in shape and adaptedto receive tube extension legs, described below, at a distal end ofjunction assembly 8. Sheath 4 has a distal end 9 that comprises a distaltip 10 that is preferably radiused to ease insertion of catheter I intoa duct, particularly the common bile duct of an individual. Distal end 9preferably conforms to the shape of a straight cylinder and is adaptedto receive a stone balloon 12 that is preferably a latex based balloon.Proximal and distal ends of balloon 12 are preferably secured to distalend 9 with Loctite® adhesive.

Radio-opaque marker bands 14 (preferably less than 6 French), areprovided about distal end 9 proximal to stone balloon 12 and arepreferably spaced about 1 cm apart. However, marker bands 14 can bespaced any known and accepted increment to enable use as a measuringdevice or feature. The placement and spacing of marker bands 14 is setso that the marker bands can be used to measure the size of stricturesand stones as well as to determine balloon position within a duct.Marker bands 14 are secured to distal end 9 with adhesive (not shown)and epoxy 18. An adhesive such as Loctite®) is used to attach markerbands 14 to distal end 9. Epoxy 18 such as Tra-Bond epoxy is used toprovide a chamfered edge to marker bands 14 as shown in FIG. 1. Distalend 9 is preferably from about 0.4″ to about 2″ long to accommodate thestone balloon and marker bands (shown as “A” in FIG. 1).

Extending proximally from distal end 9 is taper portion 16. Taperportion 16 is preferably from about 4″ to about 20″ and more preferablyfrom about 8″ to about 16″ (shown as “B” in FIG. 1). A proximal end oftaper 16 has an outside diameter of about 7 French while a distal end oftaper 16 has an outside diameter of about 5 French.

Taper portion 16 facilitates the ease by which the catheter assembly canslide through the working channel of a duodenoscope and into the Papillaof Vater to gain entry to the common bile duct of the biliary tree.

As stated, sheath 4 has three lumens. A first lumen 20 extends fromproximal end 6 to distal end 10. First lumen 20 preferably has a distalport that exists axially from distal tip 10. A portion of sheath 4 thatforms a proximal end of first lumen 20 is connected to a guide wire legextension 30. Guide wire leg extension 30 has a lumen 20 a (shown inFIG. 13) that communicates with first lumen 20. Guide wire leg extension30 has a guide wire extension leg assembly 31 that provides a fingergrasp for operating leg extension 30. A luer cap 35 has threading whichengages threading on a proximal end of leg extension 30. Guide wireextension leg 30 and first lumen 20 are preferably sized and adapted toreceive a 0.035″ guide wire. First lumen 20 and the lumen of guide wireextension leg 30 are preferably about 0.041″. To provide visualreference, the phrase “0.035 guide wire” can be printed on an exteriorsurface of guide wire extension leg 30. Extension leg 30 can also becolor-coded purple in accordance with an industry standard for a 0.035″guide wire product.

A second lumen 22 extends preferably from proximal end 6 to a pointproximal to distal tip 10. Second lumen 22 has a balloon distal port 23situated within the axial length of stone balloon 12 so that secondlumen 22 communicates with an interior surface of stone balloon 12. Aportion of sheath 4 that forms a proximal end of second lumen 22 isconnected to a balloon extension leg 32. Balloon extension leg 32 has alumen 22 a (shown in FIG. 13) that is in communication with second lumen22. Balloon extension leg 32 has a balloon extension leg assembly 33that provides a finger grasp to allow ease of manipulation. Balloonextension leg assembly 33 also comprises a stopcock 34 that ispreferably one-way and a luer lock section 37 to receive a ballooninflation/deflation device (not shown).

A third lumen 24 extends preferably from proximal end 6 to a pointproximal to stone balloon 12. Third lumen 24 has a contrast mediumdistal port 25 situated proximal to stone balloon 12. In an alternativeembodiment (as shown in FIG. 13), distal port 25 can be situated distalto stone balloon 12. A portion of sheath 4 that forms a proximal end ofthird lumen 24 is connected to a contrast medium extension leg 38.Contrast medium extension leg 38 has a lumen 24 a (shown in FIG. 13)that communicates with third lumen 24. Extension leg 38 has an injectionleg assembly 39 that provides a finger grasp to allow ease ofmanipulation. Injection leg assembly 39 also has a injection luer lock40 for receiving an injection media infusion device (not shown).

Referring to FIGS. 3-5, tube junction assembly 8 comprises an outertrifurcate snap cover 43 adapted to secure sheath 4 to extension legs30, 32 and 38. Snap cover 43 has a reduced diameter snap cover distalend 44 adapted to fit snugly about sheath 4. A tapered collar 46connects snap cover distal end 44 to a main snap cover body 48. Aproximal end of snap cover 43 is enclosed by a snap cap 50 that has anaxial bore (not shown) to receive extension legs 30, 32 and 38. Snap cap50 is preferably bonded to snap cover 43 with Loctite® adhesive 54. Apolyolefin shrink tube 52 is provided about proximal end 6 of sheath 4and the distal ends of extension legs 30, 32 and 38. Shrink tube 52 isheated onto the sheath and extension legs such that the materials of thecomponents become integrated to form a seamless connection betweensheath 4 and leg extensions 30, 32 and 38.

In a preferred embodiment, the wall thickness (interluminal and outsidewalls), of a main shaft of sheath 4 is maintained to a minimum of about0.006″. The wall thickness of distal end 9 is maintained to a minimum ofabout 0.004″. These values are essential to maintain acceptablemechanical characteristics of pushability, trackability, stiffness,kinkability, tensile strength and elongation. I have discovered thatthese wall thickness can be maintained while maximizing thecross-sectional area of third lumen 38, the contrast media lumen, thatprovides enhanced contrast media flow through catheter 1. To optimizethe flow of contrast media, the diameter of first lumen 20 was reducedto about 0.041″ in the main shaft and 0.037″ minimum in the tip lengththat is sufficient to allow for the free movement of a guide wire 60through first lumen 20.

Second lumen 22, the balloon inflation/deflation lumen, was also reducedin diameter without any appreciable effect on the inflation or deflationrates. This downsizing provided more space to enlarge third lumen 38,the contrast media lumen. To ensure desired flow, the diameter of theproximal end of second lumen 22 is maintained to allow for the insertionof a 0.014 inch diameter pin. The cross-sectional shape of second lumen22 does not have to be maintained circular but may take on otherirregular or regular shapes such as an oval I discovered that across-sectional shape that conforms to a kidney shape for third lumen 38in the main shaft (the portion of sheath 4 that does not include thetapered distal end), of sheath 4 maximized the flow rate of contrastmedium in the third lumen. The kidney shaped lumen is shown in FIG. 12.I also discovered that a cross-sectional shape that conforms to acrescent shape for third lumen 38 in distal end 9 of sheath 4 maximizedcontrast media flow rates in that portion of sheath 4 while maintainingthe set minimum wall thickness. The crescent shaped lumen is shown inFIG. 11.

To demonstrate the efficacy of the invention, a comparison test was runwith prior art products. Prior art triple lumen catheter A is shown inFIGS. 14A and 14B. Prior art triple lumen catheter B is shown in FIGS.15A and 15B. The invention catheter is shown in FIGS. 11 and 12. Allthree have 7 French main body outer diameters that reduce down to 5French distal tip outer diameters. Each has an 11.5 mm balloon attachedproximal to the distal ends of the catheters. As is clearly seen in thefigures, the invention catheter has the smallest cross-sectional areafor the balloon inflation lumen and the largest cross-sectional area forthe contrast media lumen.

To test balloon inflation/deflation rates, 1.5 cc of air was infusedinto the 11.5 mm balloons with a preloaded syringe. Three test runs weremade with the prior art balloon catheters and over thirty runs were madewith the invention balloon catheter. Prior art catheter A had a meaninflation rate of 1.18 seconds with a standard deviation of 0.13. Priorart catheter B had a mean inflation rate of 0.92 seconds with a standarddeviation of 0.13. The invention catheter had a mean inflation rate of0.74 seconds with a standard deviation of 0.08.

Prior art catheter A had a mean deflation rate of 1.00 seconds with astandard deviation of 0.03. Prior art catheter B had a mean deflationrate of 0.94 seconds with a standard deviation of 0.14. The inventioncatheter had a mean deflation rate of 0.57 seconds with a standarddeviation of 0.08.

To test contrast lumen injection rates, tests were conducted with waterbeing infused through the contrast lumen at 60 psi. The rate wasdetermined by dividing the amount of water collected at the distal endsof the catheters by the time. Tests were run for versions of ballooncatheters having contrast lumen distal ports proximal to the balloon andversions having distal ports distal to the balloon.

For versions having contrast lumen distal to the balloon, prior artcatheter A had a mean flow rate of 21.7 ml/min. with a mean deviation of0.6. Prior art catheter B had a mean flow rate of 43.7 ml/min. with amean deviation of 0.6. The invention catheter had a mean flow rate of 48ml/min. with a mean deviation of 2.

For the catheter versions having contrast lumen proximal to the balloon,prior art catheter A had a mean flow rate of 23.0 ml/min. with a meandeviation of 1.7. Prior art catheter B had a mean flow rate of 44.3ml/min. with a mean deviation of 1.5. The invention catheter had a meanflow rate of 52 ml/min. with a mean deviation of 2.

The chart set forth below lists the preferred maximum and minimumcross-sectional areas for the invention triple lumen balloon catheter.It is to be understood that these values are extremes for catheters madewith Pebax 7033. Use of other materials may allow for larger maximumsand smaller minimums while achieving and maintaining the flow rates andmechanical characteristics set forth herein. Other materials may also beused to alter the mechanical characteristics, e.g., trackability andkinkability, without altering the desired lumen cross-sectional areasand improved flow rates and without departing from the scope of theinvention.

FIG. 16 shows a cross-section of a distal tip of a catheter made inaccordance with one embodiment of the invention with the contrast medialumen maximized relative to the balloon lumen and the guide wire lumen.FIG. 17 shows a cross-section of a distal tip of a catheter made inaccordance with another embodiment of the invention with the contrastmedia lumen minimized relative to the balloon lumen and the guide wirelumen. FIG. 18 shows a cross-section of a main shaft of a catheter madein accordance with one embodiment of the invention with the contrastmedia lumen minimized relative to the balloon lumen and the guide wirelumen. FIG. 19 shows a cross-section of a main shaft of a catheter madein accordance with another embodiment of the invention with the contrastmedia lumen maximized relative to the balloon lumen and the guide wirelumen. The cross-sectional areas of the lumens shown in the drawings arereflected in the chart below.

Catheter Guide wire Lumen (in²) Balloon Lumen (in²) Contrast Lumen (in²)Location Min. Max. Min. Max. Min. Max. Tip Length 1.08 × 1.20 × 2.83 ×9.14 × 1.42 × 1.07 × 10⁻³ 10⁻³ 10⁻⁵ 10⁻⁵ 10⁻⁴ 10⁻³ Main 1.19 × 1.59 ×1.13 × 2.07 × 3.48 × 3.15 × Shaft 10⁻³ 10⁻³ 10⁻⁴ 10⁻⁴ 10⁻⁴ 10⁻³

The desired lumen geometric configurations are established by varyingthe pressures in the different lumen when sheath 4 is manufactured usingan extrusion process. Altering the pressure differentials in the lumensduring the extrusion process produces varied geometric cross-sections.One set of pressure differentials is used in the main shaft while adifferent set is used in the distal end. This was combined with what iscommonly known in the industry as the “bump” tubing extrusion process togenerate a tapered distal end with cylindrical tip. The tapered distalend is formed by increasing the extrusion speed at the appropriate pointin the formation of sheath 4.

Those of skill in the art will appreciate that the process is a dynamicone that cannot be operated at a constant set point throughout theprocess. Multipoint output speed controls allow for the smoothtransition of the outside geometry of the sheath that is preferablycircular in cross section. Multipoint pressure controls are essential toobtain the desired cross sectional areas and geometries of the threelumens.

To illustrate the process, to make the crescent shaped contrast medialumen in the distal end, the pressure in the guide wire lumen isslightly decreased from the pressure used in the main shaft which isapproximately from about 3 to 8 inches of H₂O and preferably from about4 to about 6 inches of H₂O to achieve a drop in inner diameter of from0.041 inches to 0.037 inches. The pressure in the balloon inflationlumen was reduced to close to zero without any adverse results to thedimensional integrity of the balloon inflation lumen in the distal end.The pressure in the contrast medium lumen was slightly increased withinthe range of approximately from about 3 to about 8 inches of H₂O andpreferably from about 4 to about 6 inches of H₂O. The shift in relativelumen pressures resulted in the contrast medium lumen migrating into theareas previously occupied by the balloon lumen.

Those of ordinary skill in the art will be familiar with the chemicalcompositions, materials and methods used to make such catheters. It isto be understood that the composition of sheath 4 does not form part ofthe invention. The materials described herein are merely forillustrative purposes.

It is to be appreciated that due to variances from batch to batch of aselected material and variances among different materials, someexperimentation is required with respect to the pressure and speedsettings to achieve the desired geometric configurations describedherein. The pressure ranges set forth herein are for the disclosed Pebaxmaterial. Alternative ranges may be required for different materials toachieve the desired geometric configurations. The key to formation ofthe desired geometric configurations lies with the balance of pressuredifferentials in the various lumen at any given point along theextrusion process as well as pressure alteration in the individual lumenas the extrusion progresses.

The apparatus shown in FIG. 10 is used to make sheath 4. The processbegins by placing resin 68 in a resin dryer 70 that has a hollow chamber71 for receiving resin 68. Resin 68 is maintained in dryer 70 overnightto remove any moisture present in the resin. Dryer 70 is attached to aheating chamber 72 having a hollow portion 73 for receiving a screw feed74. Screw feed 74 rotates within heating chamber 72. Hollow portion 73is in communication with hollow chamber 71. Screw feed 74 has a proximalend 75, the pre-screw feed end, that is set at a first temperature, amiddle screw feed section 76, the mid-screw section, that is set at asecond temperature and a distal screw feed end 77, the extrusion dieend, that is set at a third temperature. The temperatures are setaccording to resin melt characteristics as is well known in the art.

To form the three lumen, three high speed, ultra low pressure aircontrollers, first air controller 80, second air controller 81 and thirdair controller 82 are attached to a three lumen extrusion die 90 and aprogram controller 92. Custom software is loaded into program controller92 and controls five outputs-processing speed, the pressure in the threelumens and the length of the finished product. The Program controllerhas twenty-two adjustment points for the five output settings.

The heated resin 68 is fed through extrusion die 90. The formed catheteris then placed in a water bath 100 to cool the extruded catheter sheath.The sheath is then fed by rollers 104 past a computer operated cut-offblade 102 that cuts the tube into predetermined lengths. The severedcatheter lengths are dropped into a tray 106 where the catheters can begathered for further assembly.

To initiate the process, an extrusion run is commenced and dimensionalsamples are taken to determine whether the desired dimensionalparameters are being met. Adjustments are made to the apparatus untilthe desired dimensions are obtained. The extrusion run is dimensionallymonitored throughout the run. Data is submitted with each lot to ensureconsistency and acceptability of the product.

The inventive catheter described herein may be used in the followingmanner to evaluate, for example, a bile duct site and to position aballoon for treating a stricture or obstruction. An endoscope such as aduodenoscope is advanced through the alimentary track to the Papilla ofVater. A 0.035 inch guide wire is advanced through the working channelof the endoscope, out the endoscope's distal end and advanced throughthe Papilla of Vater into the common bile duct. A proximal end of theguide wire is inserted into a distal port of the guide wire lumen ofcatheter 1. Catheter 1 is advanced along the guide wire and through theendoscope working channel until positioned in the common bile duct orother desired duct. Alternatively, the guide wire can be preloaded intothe catheter and the combination of the catheter and guide wire can beadvanced through the endoscope to the desired duct site. Contrast mediacan then be infused through the novel contrast media lumen to enablevisualization of the duct anatomy and contents and to adjust thecatheter's positioning with respect to any potential duct occlusions orstones. Once positioning of the balloon has been finalized via theradiopaque markers, the contrast media or a combination of both,inflation media is infused through the balloon inflation/deflation lumento expand the balloon. The catheter is then manipulated to remove theobstruction or stricture.

The techniques used to operate the catheter are those that are common inthe art. The primary difference is the ease with which contrast mediacan be infused into a desired site due to the unique combination oflumen geometries and cross-sectional areas.

It is to be understood that the foregoing description of the inventionis intended merely to be illustrative thereof and that othermodifications, embodiments and equivalents may be apparent to those whoare skilled in the art without departing from its spirit.

1. A multi-lumen balloon catheter comprising: a sheath comprising a mainbody and a distal end extending distally from the main body and aplurality of lumens comprising a first lumen, second lumen, and thirdlumen; the third lumen formed in the sheath wherein a first portion ofthe third lumen extends at least partially through the main body and hasa first shape in cross section and wherein a second portion of the thirdlumen extends at least partially through the distal end and has asecond, different shape in cross section; the second lumen extending atleast partially through the main body and partially through the distalend; the first lumen extending at least partially through the main bodyand partially through the distal end; a balloon attached about thedistal end; and a taper portion extending proximally from the distalend, wherein the outside diameter of the sheath at the distal end issmaller than the outside diameter of the sheath at the proximal end ofthe taper portion, the plurality of lumens extending through the taperportion.
 2. The catheter of claim 1 wherein the cross-sectional area ofthe first portion of the third lumen is from about 3.48 ×10 ⁻⁴ inches²to about 3.15 ×10⁻³ inches².
 3. The catheter of claim 1 wherein thecross-sectional area of the second portion of the third lumen is fromabout 1.42 ×10 ⁻⁴ inches² to about 1.07 ×10 ⁻³ inches² .
 4. The catheterof claim 1 wherein the second lumen has a first portion that extends atleast partially through the main body and a second portion that extendsat least partially through the distal end.
 5. The catheter of claim 4wherein the first portion of the second lumen has a cross-sectional areafrom about 1.13 ×10 ⁻⁴ inches² to about 2.07 ×10 ⁻⁴ inches^(2 .)
 6. Thecatheter of claim 4 wherein the second portion of the second lumen has across-sectional area from about 2.83 ×10⁻⁵ inches² to about 9.14 ×10⁻⁵inches^(2 .)
 7. The catheter of claim 1 wherein the first lumen has afirst portion that extends at least partially through the main body anda second portion that extends at least partially through the distal end.8. The catheter of claim 7 wherein the first portion of the first lumenhas a cross-sectional area from about 1.19 ×10⁻³ inches² to about 1.59×10⁻³ inches².
 9. The catheter of claim 7 wherein the second portion ofthe first lumen has a cross-sectional area from about 1.08 ×10⁻³ inches²to about 1.20 ×10⁻³ inches².
 10. The catheter of claim 1 wherein themain body has an external wall and interluminal walls wherein theexternal and interluminal walls have a minimum thickness of about .006inches.
 11. The catheter of claim 1 wherein the distal end has anexternal wall and interluminal walls wherein the external andinterluminal walls have a minimum thickness of about .004 inches. 12.The catheter of claim 1 wherein the first shape is a kidney shape andthe second shape is a crescent shape.
 13. A multi-lumen balloon cathetercomprising: a sheath comprising a main body and a distal end extendingdistally from the main body and a plurality of lumens comprising a firstlumen, second lumen, and third lumen; third lumen formed in the sheathwherein a first portion of the third lumen extends at least partiallythrough the main body and has a first shape in cross section and across-sectional area from about 3.48 ×10⁻⁴ inches² to about 3.15 ×10⁻³inches² and, wherein a second portion of the third lumen extends atleast partially through the distal end and has a second, different shapein cross section and has a cross-sectional area from about 1.42 ×10⁻⁴inches² to about 1.07 ×10⁻³ inches²; the second lumen extending at leastpartially through the main body and partially through the distal end;the first lumen extending at least partially through the main body andpartially through the distal end; a balloon attached about the distalend; and a taper portion extending proximally from the distal end,wherein the outside diameter of the sheath at the distal end is smallerthan the outside diameter of the sheath at the proximal end of the taperportion, the plurality of lumens extending through the taper portion.14. The catheter of claim 13 wherein the second lumen has a firstportion that extends at least partially through the main body and asecond portion that extends at least partially through the distal endwherein the cross-sectional area of the first portion of the secondlumen is from about 1.13 ×10⁻⁴ inches to about 2.07 ×10⁻⁴ inches and thecross-sectional area of the second portion of the second lumen is fromabout 2.83 ×10 ⁻⁵inches² to about 9.14 ×10⁻⁵ inches².
 15. The catheterof claim 13 or 14 wherein the first lumen has a first portion thatextends at least partially through the main body and a second portionthat extends at least partially through the distal end wherein thecross-sectional area of the first portion of the first lumen is fromabout 1.19 ×10⁻³ inches to about 1.59 ×10⁻³ inches² and thecross-sectional area of the second portion of the first lumen is fromabout 1.08 ×10⁻³ inches² to about 1.20 ×10⁻³ inches².
 16. The catheterof claim 15 wherein the main body has an outside wall and interluminalwalls and wherein the minimum wall thickness of the outside andinterluminal main body walls is about .006 inches.
 17. The catheter ofclaim 13 or 14 wherein the main body has an outside wall andinterluminal walls and wherein the minimum wall thickness of the outsideand interluminal main body walls is about .006 inches.
 18. The catheterof claim 17 wherein the distal end has an outside wall and interluminalwalls and wherein the minimum wall thickness of the outside andinterluminal distal end walls is about .004 inches.
 19. The catheter ofclaim 18 wherein the main body has an outside diameter of about 7 Frenchand the distal end has an outside diameter of about 5 French.
 20. Thecatheter of claim 13 wherein the first shape is a kidney shape and thesecond shape is a crescent shape.
 21. A sheath comprising: a main bodyand a distal end extending distally from the main body and a pluralityof lumens comprising a contrast media lumen, a second lumen, and a thirdlumen; the contrast media lumen formed in the sheath wherein a firstportion of the contrast media lumen extends at least partially throughthe main body and has a first shape in cross section and wherein asecond portion of the contrast media lumen extends at least partiallythrough the distal end and has a second, different shape in crosssection; the second lumen extending at least partially through the mainbody and partially through the distal end; the third lumen extending atleast partially through the main body and partially through the distalend; and a taper portion extending proximally from the distal end,wherein the outside diameter of the sheath at the distal end is smallerthan the outside diameter of the sheath at the proximal end of the taperportion, the plurality of lumens extending through the taper portion.22. The sheath of claim 21 wherein the second lumen has a first portionthat extends at least partially through the main body and has a diameterof about .041 inches and a second portion that extends at leastpartially through the distal end and has a diameter of about .037inches.
 23. The sheath of claim 21 or 22 further comprising a balloonattached about the distal end.
 24. The sheath of claim 21 wherein thefirst shape is a kidney shape and the second shape is a crescent shape.25. An endoscopic method of evaluating and treating an occluded ductcomprising the steps of providing a catheter having at least threelumens comprising: a sheath having a main body and a distal endextending distally from the main body, a balloon attached about thedistal end, wherein the balloon has an inner surface, a third lumen forcontrast media, wherein the third lumen has a first portion having akidney shape in cross section and extending at least partially throughthe main body and a second portion having a crescent shape in crosssection and extending at least partially through the distal end; asecond lumen extending at least partially through the main body andpartially through the distal end and having a distal port incommunication with the inner surface of the balloon and a proximal portto receive inflation media; a first lumen extending at least partiallythrough the main body and at least partially through the distal endwherein the first lumen has a distal port in the distal end and isadapted to receive a guide wire; providing an endoscope having a workingchannel; advancing the endoscope into proximity with a duct system;advancing a guide wire through the working channel of the endoscope, outthe endoscope's distal end, and into a desired position in the ductsystem; placing the guide wire into the distal port of the first lumenand sliding the catheter over the guide wire and through the endoscope;positioning the catheter in the duct system; infusing contrast mediathrough the third lumen; and infusing inflation media into the secondlumen to expand the balloon.
 26. An endoscopic method of evaluating andtreating an occluded duct, comprising the steps of providing a catheterhaving at least three lumens comprising: a sheath having a main body anda distal end extending distally from the main body, a balloon attachedabout the distal end, wherein the balloon has an inner surface, a thirdlumen for contrast media, wherein the third lumen has a first portionhaving a kidney shape in cross section and extending at least partiallythrough the main body and a second portion having a crescent shape incross section and extending at least partially through the distal end; asecond lumen extending at least partially through the main body andpartially through the distal end and having a distal port incommunication with the inner surface of the balloon and a proximal portto receive inflation media; a first lumen extending at least partiallythrough the main body and at least partially through the distal endwherein the first lumen has a distal port in the distal end and isadapted to receive a guide wire; providing an endoscope having a workingchannel; advancing the endoscope into proximity with a duct system;preloading the guide wire into the first lumen of the catheter andadvancing the guide wire and the catheter together through the workingchannel of the endoscope, out the endoscope's distal end, and into adesired position in the duct system; infusing contrast media through thethird lumen; and infusing inflation media into the second lumen toexpand the balloon.
 27. The method of claim 25 or 26 wherein the firstportion of the third lumen has a cross-sectional area of from about 3.48×10⁻⁴ inches² to about 3.15 ×10⁻³ inches² and, wherein a second portionof the third lumen has a cross-sectional area from about 1.42 ×10⁻⁴inches² to about 1.07 ×10⁻³ inches².
 28. The method of claim 27 whereinthe first portion of the second lumen has a cross-sectional area fromabout 1.13 ×10⁻⁴ inches² to about 2.07 ×10⁻⁴ inches² and the secondportion of the second lumen has a cross-sectional area from about 2.83×10⁻⁵ inches² to about 9.14 ×10⁻⁵ inches².
 29. The method of claim 25wherein the first portion of the first lumen has a cross-sectional areafrom about 1.19 ×10⁻³ inches² to about 1.59 ×10⁻³ inches ² and thesecond section of the first lumen has a cross-sectional area from about1.08 ×10 ⁻³ inches² to about 1.20 ×10⁻³ inches
 30. The method of claim27 wherein the main body has an outside wall and interluminal walls andwherein the minimum wall thickness of the outside and interluminal mainbody walls is about .006 inches.
 31. The method of claim 30 wherein thedistal end has an outside wall and interluminal walls and wherein theminimum wall thickness of the outside and interluminal distal end wallsis about .004 inches.
 32. The method of claim 31 wherein the main bodyhas an outside diameter of about 7 French and the distal end has anoutside diameter of about 5 French.
 33. A multi-lumen balloon cathetercomprising: a sheath comprising a main body and a distal end extendingdistally from the main body and a plurality of lumens comprising a firstlumen, second lumen, and third lumen; the third lumen formed in thesheath wherein a first portion of the third lumen extends at leastpartially through the main body and has a first shape in cross sectionand wherein a second portion of the third lumen extends at leastpartially through the distal end and has a second, different shape incross section; the second lumen extending at least partially through themain body and partially through the distal end; the first lumenextending at least partially through the main body and partially throughthe distal end; a balloon attached about the distal end; wherein thethird lumen transitions from the first shape to the second shape at apoint, or over a region, that is proxmal to the balloon; and a taperportion extending proximally from the distal end, wherein the outsidediameter of the shealth at the distal end is smaller than the outsidediameter of the shealth at the proximal end of the taper portion, theplurality of lumens extending through the taper portion.
 34. Thecatheter of claim 33 wherein the cross-sectional area of the firstportion of the third lumen is from about 3.48 ×10⁻⁴ inches² to about3.15 ×10⁻³ inches².
 35. The catheter of claim 33 wherein thecross-sectional area of the second portion of the third lumen is fromabout 1.42 ×10⁻⁴ inches² to about 1.07 ×10⁻³ inches².
 36. The catheterof claim 33 wherein the second lumen has a first portion that extends atleast partially through the main body and a second portion that extendsat least partially through the distal end.
 37. The catheter of claim 36wherein the first portion of the second lumen has a cross-sectional areafrom about 1.13 ×10⁻⁴ inches² to about 2.07 ×10⁻⁴ inches².
 38. Thecatheter of claim 36 wherein the second portion of the second lumen hasa cross-sectional area from about 2.83 ×10⁻⁵ inches to about 9.14 ×10⁻⁵inches².
 39. The catheter of claim 33 wherein the first lumen has afirst portion that extends at least partially through the main body anda second portion that extends at least partially through the distal end.40. The catheter of claim 39 wherein the first portion of the firstlumen has a cross-sectional area from about 1.19 ×10⁻³ inches² to about1.59 ×10⁻³ inches².
 41. The catheter of claim 39 wherein the secondportion of the first lumen has a cross-sectional area from about 1.08×10⁻³ inches² to about 1.20 ×10⁻³ inches².
 42. The catheter of claim 33wherein the cross-sectional area of the first portion of the third lumenis from about 3.48 ×10⁻³ inches² to about 3.15 ×10⁻³ inches² and thecross-sectional area of the second portion of the third lumen is fromabout 1.42 ×10⁻⁴ inches² to about 1.07 ×10⁻³ inches².
 43. The catheterof claim 42, wherein the main body has an external wall and interluminalwalls wherein the external and interluminal walls have a minimumthickness of about .006 inches, and wherein the distal end has anexternal wall and interluminal walls wherein the external andinterluminal walls have a minimum thickness of about .004 inches. 44.The catheter of claim 33 wherein the first shape is a kidney shape andthe second shape is a crescent shape.
 45. The catheter of claim 33 or 42wherein the main body has an external wall and interluminal wallswherein the external and interluminal walls have a minimum thickness ofabout .006 inches.
 46. The catheter of claim 33 or 42 wherein the distalend has an external wall and interluminal walls wherein the external andinterluminal walls have a minimum thickness of about .004 inches.